Fixed bug #1056 Addons search last updated option text is cropped

changed addons_screen.stkgui to ensure the filterdate spinner had adequate space.

Signed-off-by: Sachith Hasaranga Seneviratne <sachith500@gmail.com>
Merge pull request #22 from sachith500/bug1056

Fixed bug #1056 Addons search last updated option text is cropped